The present invention generally relates to collimation of radiation from line-like radiation sources such as e.g. X-ray sources, and to alignment of radiation detectors thereto.
More specifically, the invention relates to arrangements and methods for producing a planar radiation beam of ionizing radiation emanating from a line-like X-ray source, to apparatus for planar beam radiography using such planar radiation beam, and to methods of aligning a detector with respect to a radiation source.
Gaseous-based ionizing radiation detectors, in general, are very attractive at low photon energies since they are cheap to manufacture, and since they can employ gas multiplication to strongly amplify the signal amplitudes. A particular kind of gaseous detector is the one, in which electrons released by interactions between photons and gas atoms can be extracted in a direction essentially perpendicular to the incident radiation. Such detector is typically a line detector provided with an elongated narrow radiation entrance slit which collimates incident radiation from a point-like radiation source into a planar beam of radiation. A two-dimensional image is then typically obtained through scanning. Optionally, a further collimator, parallel with the detector radiation entrance slit, is arranged between the radiation source and the detector.
One problem encountered when using such detectors is the difficulties obtained in aligning the detector, and possibly the collimator, with respect to the radiation source. Such alignment has to be very accurate and precise and any misalignment results inevitably in the need of realignment. Typically the detector and/or the collimator has to be aligned prior to each single measurement, which is both costly and time-consuming. Further, particular alignment means, such as e.g. optical alignment devices, may have to be provided.
Accordingly, it is an object of the present invention to provide an apparatus for planar beam radiography which can be easier and faster aligned than prior art apparatus.
It is in this respect a particular object of the invention to provide such apparatus for planar beam radiography that provides for faster and thus cheaper measurements.
A further object of the present invention is to provide such apparatus for planar beam radiography, which is effective, accurate, reliable, and which can be implemented in a simple and cost effective way.
Yet a further object of the present invention is to provide an arrangement for producing a planar beam of ionizing radiation, which can be fast and easy aligned.
Still a further object of the invention is to provide a method for aligning an ionizing radiation detector with respect to a radiation source, which is easier and faster than prior art alignment techniques.
Yet a further object of the present invention is to provide a method for producing a planar beam of ionizing radiation, which is fast and easily performed.
These objects among others are attained by apparatus, methods, and arrangements as claimed in the appended claims.
Further characteristics of the invention and advantages thereof will be evident from the following detailed description of preferred embodiments of the invention, which are shown in the accompanying drawings.